Personality, personality, personality. It goes a long way for this type of job. It also helps if you have some creative skills, are able to contribute new ideas, organization skills, and strong writing skills (if you are required to do assessments, etc.).
A good way to pick up some ideas for developing your skills in this type of field, look into some books an recreation programming, especially books that focus on dementia/cognitive impaired programs, as this type of programming can be difficult for some people to develop.